Adhesive blends for polar substrates and the resulting composite structures are finding great utility in industry at the present time. It is well known that blends of high density polyethylene (HDPE) or low density polyethylene (LDPE) or ethylene-vinyl acetate copolymers (EVA) with a high density polyethylene grafted with suitable unsaturated carboxylic acid or carboxylic acid anhydrides or other acid derivatives are adherent to certain polar polymers such as polyamides. On the other hand, adhesion to certain other polar polymers such as polyesters and saponified ethylene-vinyl acetate copolymer(ethylene-vinyl alcohol copolymer [EVOH]) is not sufficiently great in many instances.
The blends used in the composite structures of this invention provide high bond strength to polyester and ethylene-vinyl alcohol copolymers. The adhesion compared to that with blends prepared hitherto is very much improved. Also, the excellent bond strength to polyolefins, and other polar substrates, is retained. These polar substrates include polyvinyl polymers, metals, polyamides, glass, paper, wood, etc.